Triethylamine → N-hydroxy-4-(4-(3-(3-(4-(trifluoromethoxy)phenyl)-1,2,4-oxadiazol-5-yl)propoxy)phenylsulfonyl)tetrahydro-2H-pyran-4-carboxamide

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Reaction Steps

Part A. In dry equipment under nitrogen, 4-[[4-(3carboxypropoxy)phenyl]sulfonyl]tetrahydro-2H-pyran-4-carboxylic acid, 1,1-dimethylethyl ester (2.57 g, 6.0 mmol, prepared as in Example 7) was dissolved in dry N,N-dimethylformamide (12 mL), and the remaining reagents were added to the solution in the following order: 1-hydroxybenzotriazole hydrate (1.13 g, 8.4 mmol), triethylamine (1.0 mL, 7.2 mmol), 4-(trifluoromethoxy)benzamidoxime (1.58 g, 7.2 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1.73 g, 9.0 mmol). After 2 hr at 35° C., the reaction was concentrated in vacuo. The residue was taken up in ethyl acetate, washed with water, saturated sodium bicarbonate solution, and brine, dried over sodium sulfate, filtered, and concentrated in vacuo. Purification by flash column chromatography using ethyl acetate/hexanes afforded 3.05 g (81%) of the desired product as a clear glass. ESMS m/z=631 [M+Na]+.

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